Revelation Rhianna quickly opened her laptop and looked up yawning on the internet. She found out that there were three theories on yawning.

Theory 1
Yawning makes us drawn in oxygen or remove a build up of carbon dioxide.

Theory 2
Yawning might have something to do with ancestors because they wanted to show their teeth to intimidate others.

Theory 3
Boredom or drossiness causes yawning.